Justification:
Listed as Endangered as this species is believed to have undergone a decline of more than 50% in the last three generations (30-36 years, based on a generation length of 10-12 years), due to forest loss and hunting.

The species is found in north-eastern Cambodia and southern Viet Nam. Although once thought to be rare with a limited distribution, recent fieldwork has demonstrated that populations of this species are quite widespread (Lippold 1995). In Cambodia, they are found only east of the Mekong with an unknown northerly extent, although it provisionally occurs sympatrically with Pygathrix nemaeus in Voensei district, Ratanakiri (B. Rawson pers. comm.). The diversity and species identities of populations found in northernmost Cambodia, specifically Virachey National Park, is unknown. The presence of this species in Lao PDR has never been confirmed (Nadleret al. 2003). In southern Viet Nam, this species has a fragmented distribution extending from Sa Tay district (Kon Tum Province) in the north to just south of Cat Tien National Park in the south.

The largest known population exists in Seima Biodiversity Conservation Area, Mondulkiri province, Cambodia, where distance estimates provide a population estimate of approximately 42,000 individuals (95% confidence interval of 27,309 – 66,460) (Pollard et al. 2007). The densities found in Seima are probably close to carrying capacity for the species in such habitat. The largest population in Viet Nam may be in Nui Chua National Park (Ninh Thuan Province), which is estimated at 500-700 individuals (Hoang Minh Duc and Ly Ngoc Sam 2005). The only other known population estimate comes from the Nam Cat Tien sector of Cat Tien NP (Dong Nai, Binh Phuoc and Lam Dong Provinces) and is estimated at 109 individuals (Phan Duy Thuc et al. 2005). In southern Viet Nam, this species survives in a large number of small, isolated forest fragments, in comparison with the situation with the red-shanked doucs in the north, where the species is not able to persist in small forest fragments.

These animals are predominantly arboreal but may occasionally come to the ground. They are found in evergreen, semi-evergreen and semi-evergreen-mixed deciduous forest mosaics, as well as in coastal dry forest. It seems that species of this genus can adapt to relatively heavily disturbed forest (Nadler et al. 2003). Diet is apparently variable by site, being mainly composed of leaves with differing levels of supplementation with seeds, fruits and flowers (Hoang Minh Duc and Baxter 2006; Rawson 2006). Behavioral characteristics of this species make it easy to hunt (Nadler et al. 2003).

Hunting is currently the major threat to this species (Nadler et al. 2003). It is most often hunted for traditional “medicine”, mainly from people coming from the north of Viet Nam where hunting of doucs for this purpose is more common; in the southern part of Viet Nam, hunting is primarily for the pet trade.

Destruction of its natural habitat is also a threat to this species; a large portion in the centre and south of Viet Nam suffered from massive wartime damage, and the post-war human demographic explosion and extensive logging for coffee, rubber, and cashew plantations have reduced its natural habitat. Most forest at lowland elevations has been cleared and little forest remains undisturbed (Nadler et al. 2003). The translocation of some 3 million people from the north of Viet Nam to the central highlands is likely to exacerbate rates of habitat loss through the Viet Namese range of the species.

This species is listed under CITES Appendix I, as well as under Appendix 1B of Decree 32 (2006) in Viet Nam and is protected under The Law on Forestry NS/RKM/0802/016, article 49, identified as Pygathrix nemaeus in Prakas 020 PR.MAFF in Cambodia.

It is known to occur in several protected areas: Mondulkiri Protection Forest, Seima Biodiversity Conservation Area, Snuol Wildlife Sanctuary, Phnom Prich Wildlife Sanctuary (Cambodia); Bu Gia Map National Park, Cat Tien National Park, Kon Kai Kinh National Park, Kong Cha Rang Nature Reserve, Mom Ray Nature Reserve, Nui Chua National Park (Viet Nam) (Pollard et al. 2007; BirdLife unpubl. data; Timmins and Ou Rattanak 2001; Walston et al. 2001; Nadler et al. 2003). A recommended action for the conservation of this species in Viet Nam is the expansion Bu Gia Map National Park to include all unprotected contiguous forests, particularly since this is adjacent to a protected area network containing the largest population of black-shanked doucs in neighboring Cambodia. Additional survey work is also required to identify key populations.

In-Place Research, Monitoring and PlanningIn-Place Land/Water Protection and Management Conservation sites identified:Yes, over entire rangeIn-Place Species ManagementIn-Place Education Included in international legislation:Yes Subject to any international management/trade controls:Yes